feat: github actions extension linter-ignore file and ignore settings

**Is your feature request related to a problem? Please describe.**

In certain GitHub actions, deprecated fields or configurations that are caught by the GitHub actions VSCode extension's linter do still work or exist in certain versions of a GitHub action.

For example, in the screenshot below, the `command: manifest` configuration in Google's release-please GitHub action does still function, but GitHub actions VSCode extension still considers this an error.


**Describe the solution you'd like**

I want to be able to add a new comment OR surrounding comments OR a VSCode extension settings file (local to workspace, directory, or user) that will suppress the GitHub actions VSCode extension's linter from highlighting an error.

E.g., adding `// gh-actions-ignore` to a line suppresses the linter, OR adding a `.githubactionsignore` file will allow certain files to go unread by the extension (similar to `.gitignore`), OR a general regex filter in the extensions' VSCode settings

**Additional context**

N/A